/*
 * Copyright (C) 2007 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.android.dx.dex.code;

import com.android.dx.rop.code.BasicBlock;
import com.android.dx.rop.code.BasicBlockList;
import com.android.dx.rop.code.Insn;
import com.android.dx.rop.code.RopMethod;
import com.android.dx.rop.code.SourcePosition;

/**
 * Container for the set of {@link CodeAddress} instances associated with the
 * blocks of a particular method. Each block has a corresponding start address,
 * end address, and last instruction address.
 */
public final class BlockAddresses {

	/**
	 * {@code non-null;} array containing addresses for the start of each basic
	 * block (indexed by basic block label)
	 */
	private final CodeAddress[] starts;

	/**
	 * {@code non-null;} array containing addresses for the final instruction of
	 * each basic block (indexed by basic block label)
	 */
	private final CodeAddress[] lasts;

	/**
	 * {@code non-null;} array containing addresses for the end (just past the
	 * final instruction) of each basic block (indexed by basic block label)
	 */
	private final CodeAddress[] ends;

	/**
	 * Constructs an instance.
	 * 
	 * @param method
	 *            {@code non-null;} the method to have block addresses for
	 */
	public BlockAddresses(RopMethod method) {
		BasicBlockList blocks = method.getBlocks();
		int maxLabel = blocks.getMaxLabel();

		this.starts = new CodeAddress[maxLabel];
		this.lasts = new CodeAddress[maxLabel];
		this.ends = new CodeAddress[maxLabel];

		setupArrays(method);
	}

	/**
	 * Gets the instance for the start of the given block.
	 * 
	 * @param block
	 *            {@code non-null;} the block in question
	 * @return {@code non-null;} the appropriate instance
	 */
	public CodeAddress getStart(BasicBlock block) {
		return starts[block.getLabel()];
	}

	/**
	 * Gets the instance for the start of the block with the given label.
	 * 
	 * @param label
	 *            {@code non-null;} the label of the block in question
	 * @return {@code non-null;} the appropriate instance
	 */
	public CodeAddress getStart(int label) {
		return starts[label];
	}

	/**
	 * Gets the instance for the final instruction of the given block.
	 * 
	 * @param block
	 *            {@code non-null;} the block in question
	 * @return {@code non-null;} the appropriate instance
	 */
	public CodeAddress getLast(BasicBlock block) {
		return lasts[block.getLabel()];
	}

	/**
	 * Gets the instance for the final instruction of the block with the given
	 * label.
	 * 
	 * @param label
	 *            {@code non-null;} the label of the block in question
	 * @return {@code non-null;} the appropriate instance
	 */
	public CodeAddress getLast(int label) {
		return lasts[label];
	}

	/**
	 * Gets the instance for the end (address after the final instruction) of
	 * the given block.
	 * 
	 * @param block
	 *            {@code non-null;} the block in question
	 * @return {@code non-null;} the appropriate instance
	 */
	public CodeAddress getEnd(BasicBlock block) {
		return ends[block.getLabel()];
	}

	/**
	 * Gets the instance for the end (address after the final instruction) of
	 * the block with the given label.
	 * 
	 * @param label
	 *            {@code non-null;} the label of the block in question
	 * @return {@code non-null;} the appropriate instance
	 */
	public CodeAddress getEnd(int label) {
		return ends[label];
	}

	/**
	 * Sets up the address arrays.
	 */
	private void setupArrays(RopMethod method) {
		BasicBlockList blocks = method.getBlocks();
		int sz = blocks.size();

		for (int i = 0; i < sz; i++) {
			BasicBlock one = blocks.get(i);
			int label = one.getLabel();
			Insn insn = one.getInsns().get(0);

			starts[label] = new CodeAddress(insn.getPosition());

			SourcePosition pos = one.getLastInsn().getPosition();

			lasts[label] = new CodeAddress(pos);
			ends[label] = new CodeAddress(pos);
		}
	}
}
